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![Dan Williams](/assets/img/avatar_default.png)
It is not clear why the original implementation of overwrite support
required the dimm driver to be active before overwrite could proceed. In
fact that can lead to cases where the kernel retains an invalid cached
copy of the labels from before the overwrite. Unfortunately the kernel
has not only allowed that case, but enforced it.
Going forward, allow for overwrite to happen while the label area is
offline, and follow-on with updates to 'ndctl sanitize-dimm --overwrite'
to trigger the label area invalidation by default.
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Reported-by: Krzysztof Kensicki <krzysztof.kensicki@intel.com>
Fixes: 7d988097c5
("acpi/nfit, libnvdimm/security: Add security DSM overwrite support")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
553 lines
14 KiB
C
553 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright(c) 2018 Intel Corporation. All rights reserved. */
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/ndctl.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/mm.h>
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#include <linux/cred.h>
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#include <linux/key.h>
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#include <linux/key-type.h>
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#include <keys/user-type.h>
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#include <keys/encrypted-type.h>
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#include "nd-core.h"
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#include "nd.h"
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#define NVDIMM_BASE_KEY 0
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#define NVDIMM_NEW_KEY 1
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static bool key_revalidate = true;
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module_param(key_revalidate, bool, 0444);
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MODULE_PARM_DESC(key_revalidate, "Require key validation at init.");
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static const char zero_key[NVDIMM_PASSPHRASE_LEN];
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static void *key_data(struct key *key)
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{
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struct encrypted_key_payload *epayload = dereference_key_locked(key);
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lockdep_assert_held_read(&key->sem);
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return epayload->decrypted_data;
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}
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static void nvdimm_put_key(struct key *key)
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{
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if (!key)
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return;
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up_read(&key->sem);
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key_put(key);
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}
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/*
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* Retrieve kernel key for DIMM and request from user space if
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* necessary. Returns a key held for read and must be put by
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* nvdimm_put_key() before the usage goes out of scope.
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*/
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static struct key *nvdimm_request_key(struct nvdimm *nvdimm)
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{
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struct key *key = NULL;
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static const char NVDIMM_PREFIX[] = "nvdimm:";
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char desc[NVDIMM_KEY_DESC_LEN + sizeof(NVDIMM_PREFIX)];
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struct device *dev = &nvdimm->dev;
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sprintf(desc, "%s%s", NVDIMM_PREFIX, nvdimm->dimm_id);
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key = request_key(&key_type_encrypted, desc, "");
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if (IS_ERR(key)) {
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if (PTR_ERR(key) == -ENOKEY)
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dev_dbg(dev, "request_key() found no key\n");
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else
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dev_dbg(dev, "request_key() upcall failed\n");
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key = NULL;
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} else {
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struct encrypted_key_payload *epayload;
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down_read(&key->sem);
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epayload = dereference_key_locked(key);
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if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
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up_read(&key->sem);
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key_put(key);
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key = NULL;
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}
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}
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return key;
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}
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static const void *nvdimm_get_key_payload(struct nvdimm *nvdimm,
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struct key **key)
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{
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*key = nvdimm_request_key(nvdimm);
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if (!*key)
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return zero_key;
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return key_data(*key);
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}
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static struct key *nvdimm_lookup_user_key(struct nvdimm *nvdimm,
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key_serial_t id, int subclass)
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{
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key_ref_t keyref;
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struct key *key;
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struct encrypted_key_payload *epayload;
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struct device *dev = &nvdimm->dev;
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keyref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
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if (IS_ERR(keyref))
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return NULL;
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key = key_ref_to_ptr(keyref);
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if (key->type != &key_type_encrypted) {
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key_put(key);
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return NULL;
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}
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dev_dbg(dev, "%s: key found: %#x\n", __func__, key_serial(key));
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down_read_nested(&key->sem, subclass);
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epayload = dereference_key_locked(key);
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if (epayload->decrypted_datalen != NVDIMM_PASSPHRASE_LEN) {
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up_read(&key->sem);
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key_put(key);
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key = NULL;
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}
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return key;
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}
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static const void *nvdimm_get_user_key_payload(struct nvdimm *nvdimm,
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key_serial_t id, int subclass, struct key **key)
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{
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*key = NULL;
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if (id == 0) {
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if (subclass == NVDIMM_BASE_KEY)
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return zero_key;
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else
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return NULL;
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}
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*key = nvdimm_lookup_user_key(nvdimm, id, subclass);
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if (!*key)
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return NULL;
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return key_data(*key);
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}
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static int nvdimm_key_revalidate(struct nvdimm *nvdimm)
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{
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struct key *key;
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int rc;
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const void *data;
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if (!nvdimm->sec.ops->change_key)
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return -EOPNOTSUPP;
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data = nvdimm_get_key_payload(nvdimm, &key);
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/*
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* Send the same key to the hardware as new and old key to
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* verify that the key is good.
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*/
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rc = nvdimm->sec.ops->change_key(nvdimm, data, data, NVDIMM_USER);
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if (rc < 0) {
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nvdimm_put_key(key);
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return rc;
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}
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nvdimm_put_key(key);
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
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return 0;
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}
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static int __nvdimm_security_unlock(struct nvdimm *nvdimm)
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{
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struct device *dev = &nvdimm->dev;
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
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struct key *key;
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const void *data;
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int rc;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->unlock
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|| !nvdimm->sec.flags)
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return -EIO;
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/* No need to go further if security is disabled */
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if (test_bit(NVDIMM_SECURITY_DISABLED, &nvdimm->sec.flags))
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return 0;
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if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
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dev_dbg(dev, "Security operation in progress.\n");
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return -EBUSY;
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}
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/*
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* If the pre-OS has unlocked the DIMM, attempt to send the key
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* from request_key() to the hardware for verification. Failure
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* to revalidate the key against the hardware results in a
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* freeze of the security configuration. I.e. if the OS does not
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* have the key, security is being managed pre-OS.
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*/
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if (test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.flags)) {
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if (!key_revalidate)
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return 0;
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return nvdimm_key_revalidate(nvdimm);
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} else
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data = nvdimm_get_key_payload(nvdimm, &key);
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rc = nvdimm->sec.ops->unlock(nvdimm, data);
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dev_dbg(dev, "key: %d unlock: %s\n", key_serial(key),
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rc == 0 ? "success" : "fail");
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nvdimm_put_key(key);
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
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return rc;
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}
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int nvdimm_security_unlock(struct device *dev)
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{
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struct nvdimm *nvdimm = to_nvdimm(dev);
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int rc;
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nvdimm_bus_lock(dev);
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rc = __nvdimm_security_unlock(nvdimm);
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nvdimm_bus_unlock(dev);
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return rc;
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}
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static int check_security_state(struct nvdimm *nvdimm)
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{
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struct device *dev = &nvdimm->dev;
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if (test_bit(NVDIMM_SECURITY_FROZEN, &nvdimm->sec.flags)) {
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dev_dbg(dev, "Incorrect security state: %#lx\n",
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nvdimm->sec.flags);
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return -EIO;
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}
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if (test_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags)) {
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dev_dbg(dev, "Security operation in progress.\n");
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return -EBUSY;
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}
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return 0;
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}
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static int security_disable(struct nvdimm *nvdimm, unsigned int keyid)
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{
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struct device *dev = &nvdimm->dev;
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
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struct key *key;
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int rc;
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const void *data;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->disable
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|| !nvdimm->sec.flags)
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return -EOPNOTSUPP;
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rc = check_security_state(nvdimm);
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if (rc)
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return rc;
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data = nvdimm_get_user_key_payload(nvdimm, keyid,
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NVDIMM_BASE_KEY, &key);
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if (!data)
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return -ENOKEY;
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rc = nvdimm->sec.ops->disable(nvdimm, data);
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dev_dbg(dev, "key: %d disable: %s\n", key_serial(key),
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rc == 0 ? "success" : "fail");
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nvdimm_put_key(key);
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
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return rc;
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}
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static int security_update(struct nvdimm *nvdimm, unsigned int keyid,
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unsigned int new_keyid,
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enum nvdimm_passphrase_type pass_type)
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{
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struct device *dev = &nvdimm->dev;
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
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struct key *key, *newkey;
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int rc;
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const void *data, *newdata;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->change_key
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|| !nvdimm->sec.flags)
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return -EOPNOTSUPP;
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rc = check_security_state(nvdimm);
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if (rc)
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return rc;
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data = nvdimm_get_user_key_payload(nvdimm, keyid,
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NVDIMM_BASE_KEY, &key);
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if (!data)
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return -ENOKEY;
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newdata = nvdimm_get_user_key_payload(nvdimm, new_keyid,
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NVDIMM_NEW_KEY, &newkey);
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if (!newdata) {
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nvdimm_put_key(key);
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return -ENOKEY;
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}
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rc = nvdimm->sec.ops->change_key(nvdimm, data, newdata, pass_type);
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dev_dbg(dev, "key: %d %d update%s: %s\n",
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key_serial(key), key_serial(newkey),
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pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
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rc == 0 ? "success" : "fail");
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nvdimm_put_key(newkey);
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nvdimm_put_key(key);
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if (pass_type == NVDIMM_MASTER)
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nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm,
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NVDIMM_MASTER);
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else
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm,
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NVDIMM_USER);
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return rc;
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}
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static int security_erase(struct nvdimm *nvdimm, unsigned int keyid,
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enum nvdimm_passphrase_type pass_type)
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{
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struct device *dev = &nvdimm->dev;
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
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struct key *key = NULL;
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int rc;
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const void *data;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->erase
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|| !nvdimm->sec.flags)
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return -EOPNOTSUPP;
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rc = check_security_state(nvdimm);
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if (rc)
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return rc;
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if (!test_bit(NVDIMM_SECURITY_UNLOCKED, &nvdimm->sec.ext_flags)
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&& pass_type == NVDIMM_MASTER) {
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dev_dbg(dev,
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"Attempt to secure erase in wrong master state.\n");
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return -EOPNOTSUPP;
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}
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data = nvdimm_get_user_key_payload(nvdimm, keyid,
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NVDIMM_BASE_KEY, &key);
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if (!data)
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return -ENOKEY;
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rc = nvdimm->sec.ops->erase(nvdimm, data, pass_type);
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dev_dbg(dev, "key: %d erase%s: %s\n", key_serial(key),
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pass_type == NVDIMM_MASTER ? "(master)" : "(user)",
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rc == 0 ? "success" : "fail");
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nvdimm_put_key(key);
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
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return rc;
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}
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static int security_overwrite(struct nvdimm *nvdimm, unsigned int keyid)
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{
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struct device *dev = &nvdimm->dev;
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
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struct key *key = NULL;
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int rc;
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const void *data;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->overwrite
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|| !nvdimm->sec.flags)
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return -EOPNOTSUPP;
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rc = check_security_state(nvdimm);
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if (rc)
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return rc;
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data = nvdimm_get_user_key_payload(nvdimm, keyid,
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NVDIMM_BASE_KEY, &key);
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if (!data)
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return -ENOKEY;
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rc = nvdimm->sec.ops->overwrite(nvdimm, data);
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dev_dbg(dev, "key: %d overwrite submission: %s\n", key_serial(key),
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rc == 0 ? "success" : "fail");
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nvdimm_put_key(key);
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if (rc == 0) {
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set_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
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set_bit(NDD_WORK_PENDING, &nvdimm->flags);
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set_bit(NVDIMM_SECURITY_OVERWRITE, &nvdimm->sec.flags);
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/*
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* Make sure we don't lose device while doing overwrite
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* query.
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*/
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get_device(dev);
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queue_delayed_work(system_wq, &nvdimm->dwork, 0);
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}
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return rc;
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}
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void __nvdimm_security_overwrite_query(struct nvdimm *nvdimm)
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{
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struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nvdimm->dev);
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int rc;
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unsigned int tmo;
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/* The bus lock should be held at the top level of the call stack */
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lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
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/*
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* Abort and release device if we no longer have the overwrite
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* flag set. It means the work has been canceled.
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*/
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if (!test_bit(NDD_WORK_PENDING, &nvdimm->flags))
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return;
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tmo = nvdimm->sec.overwrite_tmo;
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if (!nvdimm->sec.ops || !nvdimm->sec.ops->query_overwrite
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|| !nvdimm->sec.flags)
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return;
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rc = nvdimm->sec.ops->query_overwrite(nvdimm);
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if (rc == -EBUSY) {
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/* setup delayed work again */
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tmo += 10;
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queue_delayed_work(system_wq, &nvdimm->dwork, tmo * HZ);
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nvdimm->sec.overwrite_tmo = min(15U * 60U, tmo);
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return;
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}
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if (rc < 0)
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dev_dbg(&nvdimm->dev, "overwrite failed\n");
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else
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dev_dbg(&nvdimm->dev, "overwrite completed\n");
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/*
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* Mark the overwrite work done and update dimm security flags,
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* then send a sysfs event notification to wake up userspace
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* poll threads to picked up the changed state.
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*/
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nvdimm->sec.overwrite_tmo = 0;
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clear_bit(NDD_SECURITY_OVERWRITE, &nvdimm->flags);
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clear_bit(NDD_WORK_PENDING, &nvdimm->flags);
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nvdimm->sec.flags = nvdimm_security_flags(nvdimm, NVDIMM_USER);
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nvdimm->sec.ext_flags = nvdimm_security_flags(nvdimm, NVDIMM_MASTER);
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if (nvdimm->sec.overwrite_state)
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sysfs_notify_dirent(nvdimm->sec.overwrite_state);
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put_device(&nvdimm->dev);
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}
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void nvdimm_security_overwrite_query(struct work_struct *work)
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{
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struct nvdimm *nvdimm =
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container_of(work, typeof(*nvdimm), dwork.work);
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nvdimm_bus_lock(&nvdimm->dev);
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__nvdimm_security_overwrite_query(nvdimm);
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nvdimm_bus_unlock(&nvdimm->dev);
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}
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#define OPS \
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C( OP_FREEZE, "freeze", 1), \
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C( OP_DISABLE, "disable", 2), \
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C( OP_UPDATE, "update", 3), \
|
|
C( OP_ERASE, "erase", 2), \
|
|
C( OP_OVERWRITE, "overwrite", 2), \
|
|
C( OP_MASTER_UPDATE, "master_update", 3), \
|
|
C( OP_MASTER_ERASE, "master_erase", 2)
|
|
#undef C
|
|
#define C(a, b, c) a
|
|
enum nvdimmsec_op_ids { OPS };
|
|
#undef C
|
|
#define C(a, b, c) { b, c }
|
|
static struct {
|
|
const char *name;
|
|
int args;
|
|
} ops[] = { OPS };
|
|
#undef C
|
|
|
|
#define SEC_CMD_SIZE 32
|
|
#define KEY_ID_SIZE 10
|
|
|
|
ssize_t nvdimm_security_store(struct device *dev, const char *buf, size_t len)
|
|
{
|
|
struct nvdimm *nvdimm = to_nvdimm(dev);
|
|
ssize_t rc;
|
|
char cmd[SEC_CMD_SIZE+1], keystr[KEY_ID_SIZE+1],
|
|
nkeystr[KEY_ID_SIZE+1];
|
|
unsigned int key, newkey;
|
|
int i;
|
|
|
|
rc = sscanf(buf, "%"__stringify(SEC_CMD_SIZE)"s"
|
|
" %"__stringify(KEY_ID_SIZE)"s"
|
|
" %"__stringify(KEY_ID_SIZE)"s",
|
|
cmd, keystr, nkeystr);
|
|
if (rc < 1)
|
|
return -EINVAL;
|
|
for (i = 0; i < ARRAY_SIZE(ops); i++)
|
|
if (sysfs_streq(cmd, ops[i].name))
|
|
break;
|
|
if (i >= ARRAY_SIZE(ops))
|
|
return -EINVAL;
|
|
if (ops[i].args > 1)
|
|
rc = kstrtouint(keystr, 0, &key);
|
|
if (rc >= 0 && ops[i].args > 2)
|
|
rc = kstrtouint(nkeystr, 0, &newkey);
|
|
if (rc < 0)
|
|
return rc;
|
|
|
|
if (i == OP_FREEZE) {
|
|
dev_dbg(dev, "freeze\n");
|
|
rc = nvdimm_security_freeze(nvdimm);
|
|
} else if (i == OP_DISABLE) {
|
|
dev_dbg(dev, "disable %u\n", key);
|
|
rc = security_disable(nvdimm, key);
|
|
} else if (i == OP_UPDATE || i == OP_MASTER_UPDATE) {
|
|
dev_dbg(dev, "%s %u %u\n", ops[i].name, key, newkey);
|
|
rc = security_update(nvdimm, key, newkey, i == OP_UPDATE
|
|
? NVDIMM_USER : NVDIMM_MASTER);
|
|
} else if (i == OP_ERASE || i == OP_MASTER_ERASE) {
|
|
dev_dbg(dev, "%s %u\n", ops[i].name, key);
|
|
if (atomic_read(&nvdimm->busy)) {
|
|
dev_dbg(dev, "Unable to secure erase while DIMM active.\n");
|
|
return -EBUSY;
|
|
}
|
|
rc = security_erase(nvdimm, key, i == OP_ERASE
|
|
? NVDIMM_USER : NVDIMM_MASTER);
|
|
} else if (i == OP_OVERWRITE) {
|
|
dev_dbg(dev, "overwrite %u\n", key);
|
|
if (atomic_read(&nvdimm->busy)) {
|
|
dev_dbg(dev, "Unable to overwrite while DIMM active.\n");
|
|
return -EBUSY;
|
|
}
|
|
rc = security_overwrite(nvdimm, key);
|
|
} else
|
|
return -EINVAL;
|
|
|
|
if (rc == 0)
|
|
rc = len;
|
|
return rc;
|
|
}
|